Larry Finger wrote:
Johannes,
With the latest wireless-2.6 git tree on my x86_64 system, I am getting a GPF in
ieee80211_sta_scan_work. I tracked it down to the following astatement:
if (!sband ||
(local->scan_channel_idx >= sband->n_channels &&
local->scan_band >= IEEE80211_NUM_BANDS)) {
Specifically, it is the "local->scan_channel_idx >= sband->n_channels" part of the if test. When I
added test prints of local->scan_channel_idx, local->scan_band, and sband, I got the following:
mac80211: scan_channel_idx = 0, scan_band = 0, sband = ffffffff882c2f10
mac80211: scan_channel_idx = 1, scan_band = 0, sband = ffffffff882c2f10
...
...
mac80211: scan_channel_idx = 13, scan_band = 0, sband = ffffffff882c2f10
mac80211: scan_channel_idx = 0, scan_band = 2, sband = dead4ead00000001
general protection fault: 0000 [1] SMP
As can be seen, "sband" is some kind of magic number and is an invalid pointer when scan_band is
larger than IEEE80211_NUM_BANDS, which causes the GPF.
With the following patch, it works:
Index: wireless-2.6/net/mac80211/ieee80211_sta.c
===================================================================
--- wireless-2.6.orig/net/mac80211/ieee80211_sta.c
+++ wireless-2.6/net/mac80211/ieee80211_sta.c
@@ -3237,8 +3237,7 @@ void ieee80211_sta_scan_work(struct work
}
if (!sband ||
- (local->scan_channel_idx >= sband->n_channels &&
- local->scan_band >= IEEE80211_NUM_BANDS)) {
+ local->scan_band >= IEEE80211_NUM_BANDS) {
ieee80211_scan_completed(local_to_hw(local));
return;
}
It seems to me that it should be OK to skip the scan_chan_idx >= sband->n_channels part of the test
as scan_band won't get to be >= to IEEE80211_NUM_BANDS until all the channels have been tested in
the legal bands.
Larry
Larry patch works great it puts the development tree back into a useable
state for broadcom devices. This should be pushed to wireless-2.6 if
Johannes will ack it.
-Jory
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